Electronic information management server, electronic information management client, electronic information management method and recording medium for recording electronic information management program

ABSTRACT

To secure the capacity of a storing unit by quickly searching and deleting unnecessary electronic information from the storing unit, an electronic information management server has a feature extracting unit extracting a feature of electronic information stored in a storing unit connected to a network, a deciding unit that decides whether the electronic information is to be deleted from the feature extracted by the feature extracting unit based on an instruction from a client, and a deleting unit that deletes from the storing unit via the network the electronic information decided to be deleted by the deciding unit.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an electronic informationmanagement server that manages a storing unit in which a document imagegenerated by scanning a paper document and an electronic documentcreated using application software that operates on a personal computerare stored, an electronic information management client, and acomputer-readable recording medium in which an electronic informationmanagement method and an electronic information management program arerecorded.

[0003] 2. Description of the Related Art

[0004] The form of conventional information storage is usuallyimplemented by filing a paper document. The information storage by thefiling of this paper document is excellent in easy reading, easyhandling, and convenience of portability. Particularly, it is excellentin intuitive comprehensibility. Accordingly, even today, the filing ofthe paper document is continuously being used in offices.

[0005] The creation method of such a paper document was by handwritingin the past. With the spread of a personal computer (hereinafterreferred to as “PC”), however, a paper document is usually created aselectronic information using application software on a PC.

[0006] Since electronic information has a characteristic that makes iteasy to systematically manage by computers, an electronic informationmanagement system that uses this characteristic can be constructed. Thestorage form of this electronic information is implemented in such aform as a document management server. The document management server canbe constructed both on a PC and as a file server shared and used bymultiple users over a network.

[0007] Such an electronic information management system facilitatesclassifying or retrieval of documents. Further, a file server can alsoreduce a quantity of information efficiently by sharing the documents,and has a great advantage of using electronic information, such asenabling associating between the documents.

[0008] To the contrary, although the information storage by filing of apaper document is more intuitively comprehensible as described abovethan the information storage of an electronic document, it is very weakin retrieval or classifying, and the retrieval and classifying are thegreatest shortcomings of the information storage by filing of paperdocuments.

[0009] As a way that solves such a defect, a method for reading a paperdocument by a scanner and storing it as an electronic document image inthe same manner as an electronic document is implemented.

[0010] However, when such document images and electronic documents arecontinuously stored in an electronic information management system suchas a document management server, its data capacity will increaseexplosively. Since limits are set on the storable capacity of theserver, the server capacity needs to be expanded or the data capacityneeds to be reduced by deleting a part of stored data.

[0011] The information stored in a document management server or thelike contains various pieces of information, and the contents of theinformation are diversified as well. This information also includes agreat deal of information that has a very important meaning only at aspecific period and is necessary for only a specific person. Forexample, it includes the information that was needed only at the end offiscal 2000 and the information valid for only a certain person. Most ofthis information becomes quite meaningless due to a lapse of a certainperiod or a change of circumstances.

[0012] It is undesirable from a data capacity viewpoint that thedocument image and electronic data that include meaningless(unnecessary/less important) information are stored.

[0013] If such meaningless information is stored, the meaninglessinformation is also to be retrieved for information retrieval and thequality of a retrieval result will deteriorate. Specifically, if theinformation is retrieved under a certain condition, unnecessaryinformation will also be displayed as a retrieval result in the statewhere it is mixed together with necessary information. The work ofdistinguishing and selecting truly necessary information from theunnecessary information will occur and an inconvenience will arise inthe system utilization by the user.

[0014] Further, when a paper document that is kept ready to the user'shand becomes unnecessary, the paper document may be disposed of asgarbage. At that time, if document data in which an electronic documentthat is an original copy of the paper document or the paper document isscanned is stored in a document management system, the document dataneeds also be deleted. However, in order to specify the data stored as adocument image, it is necessary to understand the contents of the paperdocument that is at hand and set a condition under which the document isspecified, thereby forcing the user to perform very troublesome work.

[0015] Moreover, since cellular phones and personal digital assistantsthat are increasing rapidly in recent years have a smaller storagecapacity than that of a general PC when they store electronicinformation, such as electronic mail and image information, theelectronic information needs to be rearranged. At this time, types ofunnecessary information are extracted from the stored electronicinformation and the unnecessary information will be deleted. However,the user is at a loss for judgment as to whether it may be reallydeleted and the user may also delete necessary information by mistake.Due to such a problem, time is required for rearranging electronicinformation and the rearrangement itself becomes troublesome.

SUMMARY OF THE INVENTION

[0016] The present invention has been made in view of solving theproblems noted above. That is, according to one aspect of the presentinvention, an electronic information management server has a featureextracting unit that extracts features of electronic information storedin a storing unit connected to a network, a deciding unit that decideswhether the electronic information is to be deleted from the featuresextracted by the feature extracting unit based on an instruction from aclient, and a deleting unit that deletes from the storing unit via thenetwork the electronic information decided to be deleted by the decidingunit.

[0017] Further, according to another aspect of the present invention,the electronic information management server has a storing unitconnected to a network that stores electronic information, a featureextracting unit that extracts features of the electronic informationstored in the storing unit, a deciding unit that decides whether theelectronic information is to be deleted from the features extracted bythe feature extracting unit based on an instruction from a client, and adeleting unit that deletes from the storing unit the electronicinformation decided to be deleted by the deciding unit.

[0018] Furthermore, according to another aspect of the presentinvention, the electronic information management server has a storingunit connected to a network that stores electronic information, afeature extracting unit that extracts features of the electronicinformation stored in the storing unit, an instructing and operatingunit that instructs the features of the electronic information, adeciding unit that decides whether the electronic information is to bedeleted from the features extracted by the feature extracting unit basedon an instruction from the instructing and operating unit, and adeleting unit that deletes from the storing unit the electronicinformation decided to be deleted by deciding unit.

[0019] Such an electronic information management server according to thepresent invention previously extracts features from the electronicinformation stored in a storing unit and decides whether the electronicinformation stored in the storing unit is to be deleted based on thefeatures instructed by a client or the like. By deleting the electronicinformation to be deleted from the storing unit based on this decisionresult, the electronic information stored in the storing unit accordingto the instruction of the features can easily be detected and deleted.

[0020] Further, according to another aspect of the present invention, anelectronic information management client instructs deletion ofelectronic information stored in a storing unit connected to a network,and has an instructing and operating unit that instructs features of theelectronic information to be deleted.

[0021] Such an electronic information management client according to thepresent invention can easily specify and delete unnecessary electronicdata that is stored in a storing unit connected to a network byinstructing the features of the electronic information to be deleted byan instructing and operating unit.

[0022] Further, according to another aspect of the present invention, anelectronic information management method has the steps of extractingfeatures of electronic information stored in a storing unit connected toa network, deciding whether the electronic information is to be deletedfrom the previously extracted features based on an instruction from aclient, and deleting from the storing unit via the network theelectronic information decided to be deleted.

[0023] Furthermore, according to another aspect of the presentinvention, the electronic information management method has the steps ofstoring predetermined electronic information, extracting the features ofthe stored electronic information, deciding whether the electronicinformation is to be deleted from the previously extracted featuresbased on an instruction from a client, and deleting the electronicinformation decided to be deleted.

[0024] Such electronic information management method according to thepresent invention previously extracts features from electronicinformation stored in a storing unit and decides whether the electronicinformation stored in the storing unit is to be deleted based on thefeatures instructed by a client or the like. By deleting the electronicinformation to be deleted from the storing unit based on this decidedresult, the electronic information stored in the storing unit accordingto the instruction of the features can easily be detected and deleted.

[0025] Further, according to another aspect of the present invention,such an electronic information management method, when electronicinformation stored in a storing unit connected to a network is deleted,has the steps of inputting features of the electronic information to bedeleted and giving a delete execution instruction to the electronicinformation to be deleted extracted by the storing unit according to theinput features.

[0026] Such an electronic information management method according to thepresent invention can easily specify and delete unnecessary electronicinformation stored in the storing unit connected to a network byinputting the features of the electronic information to be deleted.

[0027] Further, according to another aspect of the present invention,the electronic information management method has the steps of inputtingfeatures of electronic information from terminal equipment andextracting electronic information to be deleted from the electronicinformation stored in the storing unit of the terminal equipment anddeleting the electronic information extracted as a deletion object fromthe storing unit according to an instruction from the terminalequipment.

[0028] Furthermore, according to another aspect of the presentinvention, the electronic information management method has the steps ofinputting features of electronic information from terminal equipment andextracting information to be deleted from the electronic informationstored in the storing unit of the terminal equipment, transferring theelectronic information extracted as a deletion object from the storingunit to a temporary storage server via a network according to aninstruction from the terminal equipment and deleting the transferredelectronic information from the storing unit.

[0029] Such an electronic information management method according to thepresent invention can easily specify and delete unnecessary electronicinformation stored in the storing unit by extracting information to bedeleted from the information stored in a storing unit of the terminalequipment based on the features of the information input from terminalequipment, and deleting this extracted information according to aninstruction. Further, when a deletion instruction is issued, althoughthe extracted electronic information is transferred to a temporarystorage server via a network and the unnecessary electronic informationis deleted from the storing unit of the terminal equipment by deletingthe information from the storing unit, the information is left in thetemporary storage server. If the unnecessary electronic information isneeded later or deletion is specified by mistake, it can be reread fromthe temporary storage server.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Preferred embodiments of the present invention will be describedin detail based on the followings, wherein:

[0031]FIG. 1 is a block diagram for illustrating a system configurationof a first embodiment;

[0032]FIG. 2 is a block diagram for illustrating a configuration example(1) according to the first embodiment;

[0033]FIG. 3 is a block diagram for illustrating a configuration example(2) according to the first embodiment;

[0034]FIG. 4 is a block diagram for illustrating a configuration example(3) according to the first embodiment;

[0035]FIG. 5 is a block diagram for illustrating a configuration example(4) according to the first embodiment;

[0036]FIG. 6 is a block diagram for illustrating a configuration example(5) according to the first embodiment;

[0037]FIG. 7 is a block diagram for illustrating a configuration example(6) according to the first embodiment;

[0038]FIG. 8 is a block diagram for illustrating a configuration example(7) according to the first embodiment;

[0039]FIG. 9 is a block diagram for illustrating a configuration exampleof a document management server;

[0040]FIG. 10 is a diagram showing a flow of registration processing inthe document management server;

[0041]FIG. 11 is a diagram showing a flow when electronic information isstored in the document management server;

[0042]FIG. 12 is a flowchart for illustrating processing when thedocument management server stores the electronic information;

[0043]FIG. 13 is a diagram showing a flow of delete processing;

[0044]FIG. 14 is a flowchart for illustrating a flow of processing at aclient PC side;

[0045]FIG. 15 is a block diagram for illustrating a system configurationof a second embodiment;

[0046]FIG. 16 is a block diagram showing the configuration example ofthe document management server applied to the second embodiment;

[0047]FIG. 17 is a view illustrating an extraction procedure of imagefeatures;

[0048]FIG. 18 is a view illustrating a concept of subblock partitioning;

[0049]FIG. 19 is a flowchart for illustrating a flow of storing documentdata;

[0050]FIG. 20 is a diagram showing a flow of processing when a paperdocument is specified as a deletion condition;

[0051]FIG. 21 is a block diagram for illustrating a system configurationof a fourth embodiment;

[0052]FIG. 22 is a diagram showing a flow of delete processing in thesystem of the fourth embodiment;

[0053]FIG. 23 is a diagram showing a flow of the retrieval processing ofthe fourth embodiment;

[0054]FIG. 24 is a diagram showing a flow of the recovery processing ofthe fourth embodiment;

[0055]FIG. 25 is a block diagram for illustrating a system configurationof a fifth embodiment;

[0056]FIG. 26 is a diagram showing a flow of the delete processing inthe system of the fifth embodiment; and

[0057]FIG. 27 is a diagram showing a flow of the recovery processing inthe system of the fifth embodiment.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0058] The embodiments according to the present invention are describedbelow with reference to the drawings. FIG. 1 is a system block diagramfor describing a first embodiment. This system (electronic informationmanagement system) has an inputting unit 1, a storing unit 2, a featureextracting unit 3, a deciding unit 4, a deleting unit 5, and aninstructing and operating unit 6 provided with an operating unit 61 andan instructing unit 62, and is implemented by properly allotting theseconfigurations to an electronic information management server and anelectronic information management client.

[0059] The inputting unit 1 inputs document data. For example, a scanneris considered as a unit that inputs a paper document. Further, as a unitthat inputs an electronic document, an apparatus that reads informationfrom a medium in which the electronic document is stored, such as afloppy disc, a CD-ROM, and a magneto-optical disc and another PC andfile sever connected via a network or a unit (network connection port)that receives the electronic document from a document management serverare considered.

[0060] Hereupon, the paper document read by the scanner is converted toelectronic data of a raster image format. This converted electronic datais stored in the storing unit 2 and is used for extracting features.

[0061] The storing unit 2 stores a document in the inner part of thissystem. It is implemented using a device such as a HDD (hard disk drive)and a memory. The electronic information, such as the document datafetched in the inner part of this system by the inputting unit 1 isstored in this storing unit 2. When the electronic information isstored, an index number and an identifier that specify the document andare not duplicate are assigned and also stored. The document data storedin the storing unit 2 can be called using this index number.

[0062] The feature extracting unit 3 extracts characteristic informationfrom the document data stored in the storing unit 2. When document datais an electronic document, the internal data of the document data isanalyzed and the characteristic information is extracted. Thecharacteristic information of the electronic document includes thefollowing items, for example.

[0063] Title of the document

[0064] Creation date of the document

[0065] Creator of the document

[0066] File name of the document

[0067] Application name under which the document is created

[0068] Document keyword

[0069] Full text of the document (whole document)

[0070] For the “document keyword” of feature information to beextracted, the full text of the contents of the electronic document isanalyzed and the keyword is extracted. The method of extracting thekeyword uses an existing one. For example, the method divides text inthe unit of word, counts the occurrence frequencies of all words, anduses the words of higher occurrence frequencies as keywords.

[0071] Another method uses, as keywords, words highlighted in boldfacetype in text and words represented in larger sizes than othercharacters. Some electronic documents may contain none of theinformation described above. In that case, only the information that canbe extracted is extracted.

[0072] When document data is the document image data in which a paperdocument is scanned, such types of characteristic information describedabove cannot directly be obtained. Therefore, such types ofcharacteristic information as described above are obtained by performingOCR processing to the document image data and analyzing a characterstring obtained as a result of processing. This characteristicinformation is called a textual feature in this embodiment.

[0073] For the extracted textual features, the information is associatedwith the index number of the extracted document data and is stored inthe storing unit 2.

[0074] The operating unit 61 is a user interface for allowing the userto operate this system. The user specifies a condition for specifyingelectronic information to be deleted using this operating unit 61.

[0075] For example, when a document created before a specific date mustbe specified and deleted, the “Creation date of the document” isselected as the condition to be specified and the date that becomes astandard of deletion is entered.

[0076] When document data created by a specific document creator mustcollectively be deleted, the “Creator of the document” is selected asthe condition to be specified, and a name of the creator to be deletedor the number (employee number or the like) that specifies the creatoris entered.

[0077] Further, when a document including a specific keyword must bedeleted, the “Document keyword” is selected as the condition to bespecified and the keyword is entered.

[0078] After the user specifies the condition of electronic informationto be deleted, the user specifies deletion method conditions. There aremainly two types of deletion methods.

[0079] (1) The electronic information that matches the condition isdeleted as it is.

[0080] (2) After the electronic information that matches the conditionis checked, it is deleted.

[0081] For (1) of the deletion methods, the electronic information thatmatches the condition is deleted as it is. For example, when alldocuments before a fixed date are collectively deleted, the deletionmethod (1) is specified. Further, when there is the possibility ofdocument data not to be deleted even in the documents before a certaindate, the deletion method (2) that can specify that the documents aredeleted or are not deleted for each document data is specified.

[0082] After the deletion methods are specified, the date when thedelete processing is performed is specified. There are two specificationmethods of “one-shot processing” in which the delete processing isexecuted only once and “periodic processing” in which the sameprocessing is periodically performed.

[0083] If the user selects the one-shot processing, the user specifiesthat either the delete processing is immediately executed or the deleteprocessing is performed after a fixed period of time. If the userselects the periodic processing, the user specifies a periodic timecondition, such as every how many hours, every how many days, or everywhat day of the week.

[0084] After the user specifies these deletion conditions, the userpresses the processing execution button. When the button is pressed, theoperating unit 61 instructs the start of decision processing to thedeciding unit 4.

[0085] When the decision processing start is instructed from theoperating unit 61, the deciding unit 4 judges whether electronicinformation is unnecessary based on the condition the user specifies andthe characteristic information extracted by the feature extracting unit3 (the characteristic information is associated with the index number ofthe electronic information and stored in the storing unit 2).

[0086] The deciding unit 4 compares the characteristic informationextracted from all the electronic information stored in the storing unit2 with the condition the user specifies for every piece of electronicinformation and decides whether the electronic information is to bedeleted.

[0087] When the electronic information is not to be deleted, thedeciding unit 4 does not perform any processing. On the other hand, whenthe electronic information is to be deleted, the “Deletion object datalist” is created so as to make known that the electronic information isto be deleted, and the index number of the electronic information to bedeleted is entered in the list.

[0088] When decision processing terminates to all electronicinformation, the “Deletion object data list” is sent to the deletingunit 5 if the specification of the deletion method is the deletionmethod (1) “Electronic information that matches the condition is deletedas is”.

[0089] If the specification of the deletion method is the deletionmethod (2) “After electronic information that matches the condition ischecked, it is deleted”, the result of the “Deletion object data list”is sent to the instructing unit 62. The timing at which the “Deletionobject data list” is sent is the date specified by the operating unit61.

[0090] The instructing unit 62 displays a list of the electronicinformation to be deleted based on the “Deletion object data list” sentfrom the deciding unit 4. The user selects either the information thatis not deleted or the information that is really deleted from thedisplayed electronic information list.

[0091] In selection, when the user must check the electronicinformation, the user selects the electronic information and presses thecontents check button. When the button is pressed, the instructing unit62 displays characteristic information such as creation date, creator,title, and keyword. If necessary, the instructing unit 62 displays thecontents of electronic information.

[0092] After the user determines the electronic information to bedeleted, the user presses the delete processing start button. When thebutton is pressed, the instructing unit 62 updates the “Deletion objectdata list” based on the result from which the user selects theinformation to be deleted or not to be deleted for each piece ofelectronic information. The instructing unit 62 sends the updated“Deletion object data list” to the deleting unit 5.

[0093] The deleting unit 5 receives the “Deletion object data list” andperforms delete processing to the electronic information stored in thestoring unit 2 based on the contents of the list. There are two methodsof the delete processing. One is “Erase processing” that completelyerases stored data and the other is “Hold processing” that adds adeletion mark to the electronic information, but will not actuallydelete the data.

[0094] Usually, the latter “Hold processing” is performed. Only when aninstruction is given from the user, the “Erase processing” is performed.This is a measure for the case where deletion specification of datamight have been made by mistake.

[0095] Further, for the “Hold processing”, the capacity of the storingunit 2 will not be reduced. Accordingly, if the free space of thestoring unit 2 is reduced, the user is urged to perform the “Eraseprocessing”. This system can also be set so as to perform the eraseprocessing instead of urging the user to perform the erase processing.

[0096] In accordance with the condition the user specifies, such asystem can quickly delete the electronic information that matches thecondition and store only the information necessary for the user bysecuring free space of the storing unit 2 and deleting unnecessaryinformation. Further, only the information useful for informationretrieval is to be retrieved and the quality of a retrieval result canbe improved.

[0097] Next, a specific configuration example is described. FIGS. 2 to 8are block diagrams for describing various configuration examples. In theconfiguration example shown in FIG. 2, a document management server thatis an electronic information management server, a scanner that is theinputting unit 1 to which a document is input and a client PC having theinstructing and operating unit 6 are connected over a network N. Inaddition, multiple client PCs, scanners, and document management serversmay be connected over the same network N.

[0098] The client PC is operated by the user. The instructing andoperating unit 6 of the client PC can give an operation instruction tothe document management server and the scanner via the network N.

[0099] The document management server has the feature extracting unit 3of the electronic information of document data, storing unit 2 thatstores and registers the electronic information and the features,deciding unit 4 that decides the electronic information to be deleted inaccordance with the predetermined condition, and deleting unit 5 thatdeletes the electronic information decided to be deleted by the decidingunit 4 from the storing unit 2.

[0100] Further, when the client PC is not connected to the network N,the configuration as shown in FIG. 3 may be acceptable. That is, in theconfiguration, the document management server has the storing unit 2,feature extracting unit 3, deciding unit 4, deleting unit 5, andinstructing and operating unit 6.

[0101] Similarly, when the client PC is not connected to the network N,the configuration as shown in FIG. 4 may also be acceptable. In thisconfiguration, the document management server has the storing unit 2,feature extracting unit 3, deciding unit 4, and deleting unit 5, and thescanner has the inputting unit 1 and the instructing and operating unit6.

[0102] Further, in the configuration shown in FIG. 5, an example isgiven in which a file server is connected to the network N and thestoring unit 2 is provided in this file server. In this case, the clientPC has the instructing and operating unit 6 and the scanner has theinputting unit 1. The document management server has the featureextracting unit 3, deciding unit 4, and deleting unit 5.

[0103] Further, like the configuration shown in FIG. 6, the scanner mayalso be connected to the client PC instead of being connected directlyto the network.

[0104] Furthermore, like the configuration shown in FIG. 7, when thedocument data to be registered is only an electronic document instead ofa paper document, the configuration in which the client PC and thedocument management server are provided is acceptable.

[0105] As shown in FIG. 8, the configuration in which only the client PCconnected to the network N is provided may also be acceptable. In thiscase, the instructing and operating units 6 is also provided in all ofthe multiple client PCs. Then the electronic information managementserver is constructed by installing software that constitutes theelectronic information management server of this embodiment in at leastone of the client PCs from a medium such as a CD-ROM in which thesoftware is stored.

[0106] Accordingly, the client PC in which a program is installed willfunction as the electronic information management server on which theinstructing and operating unit 6, feature extracting unit 3, storingunit 2, deciding unit 4, and deleting unit 5 are provided.

[0107] Next, a configuration example of the document management serveris described with reference to FIG. 9. The main components of thedocument management server are a storing unit 2, a feature extractingunit 3, a deciding unit 4, a deleting unit 5, and an externallyinterfacing unit 7.

[0108] Among them, the storing unit 2, feature extracting unit 3,deciding unit 4, and deleting unit 5 are the same components asdescribed previously. The externally interfacing unit 7 is a unit thatsends and receives electronic information and operation instructioninformation to and from external equipment, such as connection with anetwork.

[0109] The registration processing of the document data in such adocument management server is described along the flow diagram of FIG.10. First, after a paper document is set in the scanner, a scan startinstruction is sent from the client PC to the scanner (A0).

[0110] Next, when the scanner receives the scan start instruction, itstarts scanning the paper document. For the scan start instruction, thestart button may also be pressed on the operator panel of the scanner.When the scanning is completed, the scanner sends a scan completionstatus signal to the client PC of the user. Subsequently, the documentdata obtained by scanning the paper document is sent to the documentmanagement server (B).

[0111] Then when the client PC receives the scan completion statussignal, it outputs a scan completion message to the user (displays it onthe screen). Since the output of this scan completion message is notalways necessary, the scan completion status signal may be ignored (A1).

[0112] When the document management server receives document data, itregisters the document data. When the document management servercompletes the registration of the document data, it sends a registrationcompletion status signal to the client PC (C9).

[0113] When the client PC receives the registration completion statussignal from the document management server, it outputs a registrationcompletion message to the user (displays it on the screen). Since theoutput of this registration completion message is not always necessary,the registration completion status signal may be ignored (A2). The useroperation on the client PC can also be performed from the operator panel(instructing and operating unit) of the document management server.

[0114]FIG. 11 is a flow diagram showing a flow when the electronicinformation of an electronic document format created using applicationsoftware on the client PC is stored in the document management server.First, the electronic document on the client PC is specified and theregistration processing of the electronic document to the documentmanagement server is started. Subsequently, the electronic document istransferred to the document management server (A0).

[0115] When the document management server receives electronic document,it performs processing in which the electronic document is registered inthe storing unit. When the document management server completes theregistration of the electronic document, it sends a registrationcompletion status signal to the client PC (C).

[0116] When the client PC receives the registration completion statussignal from the document management server, it outputs a registrationcompletion message to the user (displays it on the screen). Since theoutput of this registration completion message is not always necessary,the registration completion status signal may be ignored (A2).

[0117] Further, when the scanner is directly connected to the client PC,since scanned data is directly created on the client PC, the sameprocessing that registers the electronic document described herein tothe document management server is performed. Further, the user operationon the client PC can also be performed from the operator panel(instructing and operating unit) of the document management server.

[0118]FIG. 12 is a flowchart for describing the processing when thedocument management server stores electronic information. First, whenthe document management server receives the electronic information (stepS101), it judges whether the electronic information is the document datascanned from a paper document or an electronic document created usingapplication software or the like (step S102).

[0119] For an electronic document, the electronic information is sent tothe feature extracting unit and feature extraction processing isperformed (step S103). On the other hand, for document data read by ascanner or the like, character recognition processing such as OCR isperformed to the document data (step S104). The character recognitionresult is sent to the feature extracting unit and the feature extractionprocessing is performed (step S103).

[0120] In the feature extraction processing, features are extracted asdescribed above. The extracted features are stored in the storing unitin feature storage processing (step S105). Further, the electronicinformation itself received by the document management server is alsostored in the storing unit (step S106).

[0121] Subsequently, association processing is performed (step S107). Inthe association processing, an identifier that associates electronicinformation with the corresponding features is attached to identifywhich electronic information the extracted features are extracted from.Accordingly, the electronic information and the corresponding featuresare stored in the document management server.

[0122] Next, delete processing is described along the flow diagram ofFIG. 13. First, the user specifies the condition of the electronicinformation to be deleted by the operation of the client PC (AO).

[0123] Hereupon, when a document created before a specific date must bespecified and deleted, the “Creation date of the document” is selectedas the condition to be specified and the date that becomes a standard ofdeletion is entered.

[0124] When the document data created by a specific document creatormust collectively be deleted, the “creator of the document” is selectedas the condition to be specified and a name of a creator to be deletedand the number (employee number or the like) that specifies the creatoris entered.

[0125] Further, when a document including a specific keyword must bedeleted, the “Document keyword” is selected as the condition to bespecified and the keyword is entered.

[0126] After the user specifies the condition of electronic informationto be deleted, the user specifies deletion method conditions. Asdescribed above, there are two deletion methods: deletion method (1) theelectronic information that matches the condition is deleted as it is;and deletion method (2) after the electronic information that matchesthe condition is checked, it is deleted.

[0127] After the deletion method is specified, the date on which thedelete processing is performed is specified. There are two specificationmethods of “one-shot processing” in which the delete processing isexecuted only once and “periodic processing” in which the sameprocessing is periodically performed.

[0128] When the user selects the single processing, the user specifieswhether the delete processing is immediately executed or the deleteprocessing is performed after a fixed period of time. When the userselects the periodic processing, the user specifies a periodic timecondition, such as every what time, every what day, or every what day ofthe week. The specification order of the deletion conditions is notlimited to that described here.

[0129] After the specification of these deletion methods is completed,the information about the deletion conditions is transferred from theclient PC to the document management server. Then the user instructsprocessing execution to the document management server.

[0130] When the document management server receives the informationabout the deletion conditions and the instruction of processingexecution from the client PC, it sends the deletion conditioninformation and a decision processing start instruction to the decidingunit in the document management server. The deciding unit retrieves theelectronic information having features that match decision conditioninformation from the storing unit based on the received information.Subsequently, an index number attached to the electronic information ofthe retrieved result is written to the “Deletion object data list”.

[0131] If the deletion method in the deletion conditions is “After theelectronic information that matches the condition is checked, it isdeleted”, the “Deletion object data list” is transferred to the clientPC when decision processing is completed. On the other hand, if thedeletion method in the deletion conditions is “The electronicinformation that matches the conditions is deleted as is”, processingjumps into the processing of C2 in FIG. 13.

[0132] When the client PC receives the “Deletion object data list” fromthe document management server, it outputs an outline of the electronicinformation in the list to the client PC (displays it on the screen) tocheck whether the electronic information of the list may be reallydeleted. Accordingly, first, an index number of the electronicinformation written in the list is read.

[0133] Since the contents of the information cannot be checked usingonly an index number, an outline information acquisition request of theelectronic information is sent to the document management server to readfrom the document management server the electronic information thatcorresponds to the index number (A1).

[0134] When the document management server receives an instruction ofthe outline information acquisition request from the client PC, itfetches the outline information of the electronic information thatcorresponds to the index number and transfers it to the client PC (C1).

[0135] When the client PC acquires the outline information from thedocument management server, it lists the contents onto the client PC(displays them on the screen). The user selects the information that mayreally be deleted from this listed electronic information. In this case,the electronic information to be deleted may also be selected, and, tothe contrary, the electronic information not to be deleted may also beselected.

[0136] When selection is completed, the index number of the electronicinformation that may really be deleted is transferred from the client PCto the document management server as deletion confirmation information.Subsequently, a delete processing execution instruction is sent from theclient PC to the document management server (A2).

[0137] When the document management server receives the deletionconfirmation information and the delete processing execution instructionfrom the client PC, it sends the deletion confirmation information tothe deleting unit in the document management server as a deletion objectdata list (C2).

[0138] The deleting unit receives the deletion object data list andperforms delete processing to the electronic information stored in thestoring unit based on the contents of the list. When the deleteprocessing is completed by the storing unit, the document managementserver sends a delete processing completion status signal to the clientPC.

[0139] When the client PC receives the delete processing completionstatus signal from the document management server, it outputs aprocessing completion message to the user (displays it on the screen).Since the output of this delete processing completion message is notalways necessary, the delete processing completion status signal may beignored. Further, the user operation on a series of these client PCs canalso be performed from the operator panel (instructing and operatingunit) of the document management server.

[0140] Next, a flow of processing at the client PC side when deleteprocessing is performed is described along the flowchart of FIG. 14.

[0141] First, a deletion condition is specified by the instructing andoperating unit of the client PC (step S201). As this deletion condition,as described previously, when a document created before a specific datemust be specified and deleted, the “Creation date of the document” isselected as the condition to be specified and the date that becomes astandard of deletion is entered.

[0142] Further, when the document data created by a specific documentcreator must collectively be deleted, the “Creator of the document” isselected as the condition to be specified and a number of a creator andthe number (employee number or the like) that specifies the creator isentered.

[0143] Furthermore, when a document including a specific keyword must bedeleted, the “Document keyword” is selected as the condition to bespecified and the keyword is entered.

[0144] Next, the user specifies deletion method conditions (step S202).As described above, there are mainly two kinds of deletion methods:deletion method (1) The electronic information that matches thecondition is deleted as it is; and deletion method (2) After theelectronic information that matches the condition is checked, it isdeleted.

[0145] After the deletion methods are specified, the date when thedelete processing is performed is specified (step S203). There are twospecification methods of “one-shot processing” in which the deleteprocessing is executed only once and “periodic processing” in which thesame processing is periodically performed.

[0146] After these specifications are performed, the user sends aprocessing execution instruction from the client PC to the documentmanagement server (step S204).

[0147] When the client PC sends the processing execution instruction,the client PC judges whether “The electronic information that matchesthe condition is deleted as it is” is selected for the user-specifieddeletion condition (step S205), and when it is deleted as it is, theclient PC has delete processing done by the document management serveras it is.

[0148] On the other hand, when “After the electronic information thatmatches the condition is checked, it is deleted” is selected for theuser-specified deletion condition, the deletion object data listtransferred from the document management server is displayed and theselection of a deletion object document is performed (step S206).

[0149] Then after the deletion object document is selected, a processingexecution instruction is sent to the document management server (stepS207). Accordingly, only the selected electronic information is deletedfrom the storing unit.

[0150] As a result of such processing, in accordance with a conditionthe user specifies, the electronic information that matches thecondition can automatically be deleted and only the informationnecessary for the user can be stored by securing the free space of thestoring unit 2 and deleting unnecessary information. Only theinformation useful for information retrieval is to be retrieved and thequality of a retrieval result can be improved.

[0151] The delete processing on the client PC described above may alsobe implemented as the software having the program that corresponds toeach step. That is, the delete processing function can be implementedusing the client PC by installing this software in the client PC.

[0152] Next, a second embodiment of the present invention is described.In the second embodiment, the case where the paper document held by theuser is to be deleted is used as an example. A document printed on paperis excellent in easiness of intuitive understanding and portability. Inmany cases, therefore, the document is created using PC applicationsoftware and is printed on the paper.

[0153] When the document printed on this paper is discarded, the paperdocument may be disposed of as garbage. However, the electronic documentdata that is the source of the paper document and created using theapplication software will be left as it is without being discarded(deleted).

[0154] The second embodiment is characterized in that the originalelectronic document data is correctly deleted using the paper documentas a deletion condition when the paper document is deleted.

[0155]FIG. 15 is a system block diagram for describing the secondembodiment. This system has the configuration in which the client PC,scanner, and document management server are respectively connected tothe network N. Among them, the instructing and operating unit 6 isprovided in the client PC and the inputting unit 1 is provided in thescanner. Further, the feature extracting unit 3, image featureextracting unit 31, storing unit 2, deciding unit 4, and deleting unit 5are provided in the document management server.

[0156]FIG. 16 is a block diagram showing a configuration example of thedocument management server applied in the second embodiment. The featureextracting unit 3 is the same unit as the first embodiment, and extractscharacteristic information from document data or the like stored in thestoring unit 2.

[0157] The image feature extracting unit 31 extracts image features. Theimage features are obtained by handling the page configuration of adocument as an image and numerically calculates the aspect ratio of theimage, the distribution of image colors or image brightness, and thedistribution of image characters and line edges.

[0158] Hereupon, the extraction procedure of the image features by theimage feature extracting unit 31 is described with reference to FIG. 17.

[0159] Raster image expansion 3 a: when document data is an electronicdocument, image-specific information cannot be obtained as it is.Therefore, the electronic document is expanded as one raster image dataitem for each page and image features are extracted from the rasterimage data of the page. The electronic document into a raster image isexpanded in the same method as a general laser printer. This functionmay also be mounted using software and using dedicated hardware forexpanding the raster image. If the document data is scanned from a paperdocument, this processing is not necessary.

[0160] Aspect ratio calculation 3 b: first, the aspect ratio of rasterimage data is calculated. For the aspect ratio, the number of verticaland horizontal pixels of the raster image data is calculated and theratio of the number of vertical and horizontal pixels is considered tobe aspect ratio.

Aspect ratio=(Number of vertical pixels of image)/(Number of horizontalelements of image)

[0161] Color space conversion 3 c: next, the color space of raster imagedata is converted. The image data is represented by various anddiversified color spaces, such as black and white, monochrome, RGBcolors, YMCK colors, and YCbCr colors. If the color spaces used in thisrepresentation differ, the same image has a numerically different value.So the same color space needs to be used in order to compare thecharacteristics of an image color. Accordingly, the color space of theraster image data is converted to one color space. In this embodiment,the color space of the raster image data is converted to the RGB colorspace. It may also be converted to another color space. For example,L*a*b*, YCbCr, YUV, and YMCK are also acceptable.

[0162] Resolution conversion 3 d: next, the resolution of the rasterimage data is converted. The raster image data has various sizesaccording to the resolution of the scanner when a paper document isscanned, the resolution when an electronic document is expanded into araster image or the sizes (JIS-A4, A3 or the like) of the originaldocument, and the directions (lengthwise and sidewise) of the document.Since it is difficult to uniformly compare the color distribution statesof the raster image data of various sizes, the size of the raster imagedata needs to be standardized. Accordingly, in this embodiment, allraster image data sizes are converted to 1,000 pixels×1,000 pixelsaccording to the resolution. Other sizes are also acceptable.

[0163] Subblock partitioning 3 e: next, the raster image data ispartitioned into meshes having small blocks (subblocks). FIG. 18 shows aconcept of the subblock partitioning. Various numeric values areconsidered as the number of blocks to be partitioned. In thisembodiment, a block is partitioned into 10×10=100 subblocks. The size ofone subblock is 100 pixels×100 pixels. The image features are extractedevery this subblock.

[0164] Color distribution calculation 3 f: when the mean value of thecolors of a subblock image is calculated, three RGB values are obtainedfrom one subblock image. For example, as a result of color spaceconversion, when the image data is assumed to have converted to eightbits per pixel for the RGB respectively, the mean value of the colors ofthe subblock is a maximum of 255 and a minimum of 0 for the RGBrespectively.

[0165] Since there are 10×10=100 subblocks, the information about themean value of the colors of one raster image data item is 3×100=300subblocks. The information about the mean value of the colors of these300 subblocks is handled as a 300-dimensional vector. Since this300-dimensional vector also includes the information about the subblockposition, the 300-dimensional vector can be grasped as the colordistribution information of the raster image data.

[0166] Brightness distribution calculation 3g: when the mean value ofthe brightness of a subblock image is calculated, one value is obtainedfrom one subblock image. Similarly to the color distribution informationdescribed above, the brightness distribution information of the rasterimage data becomes a 10×10×1=100-dimensional vector. As specific valuesof the image brightness, there are luminance and lightness, for example.

[0167] Edge distribution extraction 3h: also for the edge distributioninformation of the raster image data, if edge information is extractedfrom a subblock image in the same manner, one value is obtained from onesubblock image. Accordingly, the edge distribution information having a10×10×1=100-dimensional vector is obtained.

[0168] In this embodiment, the aspect ratio (one-dimensional), colordistribution information (300-dimensional), brightness distributioninformation (100-dimensional), and edge distribution information(100-dimensional) obtained above is called image features in all. Thetotal of dimensional numbers of the image features produces a501-dimensional vector.

[0169] Then the textual features extracted by the feature extractingunit 3 shown in FIG. 16 and the image features extracted by the imagefeature extracting unit 31 are put together. The information isassociated with the index number of the extracted document data and isstored in the storing unit 2.

[0170] Since the storing unit 2, deciding unit 4, and deleting unit 5are identical with those of the first embodiment, a detailed descriptionis omitted here.

[0171] Next, the registration processing in the second embodiment isdescribed. The registration processing in the second embodiment isbasically identical with that of the first embodiment. However, a flowof the processing differs when the document management server storesdocument data.

[0172]FIG. 19 is a flowchart for describing a flow when the documentmanagement server stores document data. First, when the documentmanagement server receives document data (step S301), it decides whetherthe document data is scanned from a paper document or is of anelectronic document format created using application software or thelike (step S302).

[0173] Hereupon, for the document data of the electronic documentformat, electronic document data is expanded into one raster image dataitem for each page (step S303). On the other hand, for the document dataread by a scanner or the like, character recognition processing such asOCR is performed to the document data (step S304).

[0174] Subsequently, feature extraction processing is performed based ondocument data (step S305). In the feature extraction processing, thefeatures described above are extracted. Subsequently, image featureextraction processing is performed (step S306). In the image featureextraction processing, image features, such as the aspect ratio, colordistribution, color distribution, brightness distribution, or edgedistribution, are extracted as described above.

[0175] The extracted textual features and the image features are storedin the storing unit together with document data (steps S307 and S308).Then in associating processing, an identifier that associates thedocument data with the features is attached in order to identify whichdocument data the features are extracted from (step S309). With theabove processing, registration processing into the document managementserver is completed.

[0176] Next, delete processing in the second embodiment is described.This delete processing can specify a paper document as the deletioncondition. A flow of the processing when the paper document is specifiedas the deletion condition is described below along FIG. 20.

[0177] First, after the user loads the paper document to be deleted onthe scanner, the client PC sends a scan start instruction to the scanner(A0). When the scanner receives the scan start instruction, it startsscanning the paper document. The scanner starts the scanning also whenthe scan start button on the operator panel of the scanner is pressed.When the scanning is completed, the scanner sends a scan completionstatus signal to the client PC of the user. Subsequently, the scannersends the scanned document data to the document management server (B).

[0178] When the client PC receives the scan completion status signal, itoutputs a scan completion message to the user (plays it on the screen).Since the output of this scan completion message is not alwaysnecessary, the scan completion status signal may be ignored (A1).

[0179] When the document management server receives document data fromthe scanner, it performs character recognition processing such as OCR tothe document data and sends a character recognition result to thefeature extracting unit. The feature extracting unit extracts textualfeatures as described above. Further, the image feature extracting unitextracts image features, such as the aspect ratio, color distribution,brightness distribution, and edge distribution, as described above. Thenthe extracted textual features are transferred to the client PC. Theimage features are retained at the document management server sideinstead of being transferred (C0).

[0180] When the client PC receives textual feature data from thedocument management server, the contents of the features are output(displayed on the screen) (A2). In this embodiment, there are thefollowing specification methods of a deletion condition.

[0181] (1) Specification is made so that the document data having thefeatures output (displayed on the screen) will be deleted.

[0182] (2) A deletion condition is specified based on the data of thefeatures output (displayed on the screen).

[0183] Hereupon, when specification is made so that the document datahaving the features output of (1) will be deleted, no other deletioncondition is specified. On the other hand, when the deletion conditionis specified based on the data of the features output of (2), thespecification is identical with that of the deletion condition in thefirst embodiment.

[0184] Further, in the same manner as the first embodiment, deletionmethod conditions are specified as to whether they are deleted as theyare or they are deleted after they are checked, and the date on whichthe delete processing is performed is specified. After the specificationof these deletion conditions is completed, the client PC transfersdeletion condition information to the document management server. Theuser instructs processing execution to the document management server.

[0185] When the document management server receives the deletioncondition information and a processing execution instruction from theclient PC, it sends the deletion condition information and the decisionprocessing start instruction to the deciding unit in the documentmanagement server. The deciding unit retrieves the document data havingthe features that match the deletion condition information from thestoring unit based on the received information.

[0186] When the deletion condition is “Specification is made so that thedocument data having features will be deleted”, the document data isretrieved based on the image features retained in the documentmanagement server. For the document data stored in the storing unit, theimage features are extracted when the data is registered, and theseimage features are associated with the document data in the same manneras the textual features and stored.

[0187] The image features have the 501-dimensional vector format asdescribed previously. Further, the image features of the document datastored in the storing unit have also the 501-dimensional vector format.The deciding unit compares all the stored image features with a keyimage feature and calculates the degree of similarity for each imagefeature.

[0188] There are various calculation methods of the degree of similarityof the image features. In this embodiment, the degree of similarity iscalculated according to the following method. That is, since the imagefeatures have the 501-dimensional vector format, the distance of the twovectors between the vector of the key image feature and the vector ofthe stored image features and a distance value are used as the degree ofsimilarity. As this distance is short, it indicates that the two vectorsare close to each other and the two vectors are similar.

[0189] The deciding unit calculates several high-order index numbers ofdocument data having vectors of which the degree of similarity is high(short distance value). When the deletion condition is “The deletioncondition is specified based on the data of the features”, the documentdata having the features that match the deletion condition informationis retrieved from the storing unit in the same manner as the decisionprocessing of the first embodiment. Subsequently, the index number ofthe document data of the retrieval result is written to the “Deletionobject data list”.

[0190] When the deletion method in the deletion condition is “After thematched document is checked, it is deleted”, the “Deletion object datalist” is transferred to the client PC when decision processing iscompleted (C1). When the deletion method in the deletion condition is“The document that matches the condition is deleted as it is”,processing jumps to the processing of C3.

[0191] The processing of A3 to A5 or C2 to C3 is identical with that ofthe first embodiment. This user operation on a series of client PCs canalso be performed from the operator panel of the document managementserver.

[0192] As a result of the above processing, in this embodiment, when thepaper document the user is holding is used as a deletion condition, thedocument data that matches this condition can automatically be deleted,and only the information necessary for the user can be stored bysecuring the free space of the storing unit and deleting unnecessaryinformation. Further, only the information useful for informationretrieval is to be retrieved and the quality of the retrieval result canbe improved.

[0193] Next, a third embodiment of the present invention is described.In the third embodiment, the condition of the “Batch deletion of arelated document” can be specified when a condition of the document datato be deleted is specified.

[0194] The related documents handled in this embodiment are as follows:

[0195] (Simultaneously Input Paper Document)

[0196] If a paper document has multiple pages when the paper document isinput using an image inputting unit, such as a scanner, the series ofpaper documents are to be related documents. Further, simultaneouslyinput document data may also be used as the related documents.

[0197] (Document Data Related to Contents)

[0198] Further, when document data is registered and stored in thedocument management server, the document management server judges thedescription contents of the document data, retrieves other document datarelated to the document data, and automatically specifies it as arelated document based on the retrieval result. The user can alsospecify multiple document data items that construct the relateddocument.

[0199] The document data that is a related document is stored in thestoring unit by attaching an identifier indicating the related documentwhen it is stored in the document management server.

[0200] In the document management system of this embodiment, when thecondition of “batch deletion of a related document” is specified by theoperating unit when the registered is deleted, the deciding unit checkswhether the related document information is added to each document dataitem contained in the “Deletion object data list” created according tothe method described in the first embodiment.

[0201] If the document data to which related document information isadded is found in the list, all related documents are added to thedeletion object data list referring to the related document information.Tag information that indicates whether the document is a relateddocument is added to the list and whether the document is the relateddocument is instructed to the user.

[0202] According to such an embodiment, not only document data thatmatches the specified condition but also other document data related tothe document data are extracted to be deleted and the document data canefficiently be deleted.

[0203] Next, a fourth embodiment of the present invention is described.The fourth embodiment is characterized in that the user stores the datadeleted from the document management server into another server.

[0204] That is, in this embodiment, when a deletion instruction of thedocument data the user holds is issued, the document data is fetchedfrom the document management server and stored in a device (temporarystorage server) for storing document data separate from the documentmanagement server of the user.

[0205] This is used to recover temporarily stored document data on thedocument management server of the user when the user requests that thedocument data once deleted must be recovered.

[0206]FIG. 21 is a system block diagram for describing this embodiment.A temporary storage server HS is installed in the service center or thelike where a company that sells and maintains document managementservers BS installs one of its document management servers BS. At thistime, the document management server BS and the temporary storage serverHS installed in the user environment need to be connected to the networkN.

[0207] In addition, the temporary storage server HS may also beinstalled in the user's network environment. Further, since the functionof the temporary storage server HS can also be mounted using software, afunction equivalent to the temporary storage server HS can beimplemented by installing the software on which the function of thistemporary storage server is mounted in the client PC or the likeconnected to the user network environment.

[0208]FIG. 22 is a flowchart showing a flow of the delete processing inthe system of this embodiment. When viewed from the client PC side ofthe user, the delete processing of the present embodiment is the same asthe delete processing described in the first embodiment.

[0209] The difference is that after the document management serverreceives a delete processing execution instruction from the client PC,document data is really deleted for the first embodiment, but, in thisembodiment, the document to be deleted is transferred to the temporarystorage server separate from the document management server instead ofdeleting the document data to be deleted.

[0210] When the temporary storage server receives document data to bedeleted, the document data is stored by attaching an identificationnumber to it and stored. When storage is completed, the temporarystorage server sends a storage processing completion status signal tothe document management server (D0).

[0211] When the document management server receives the storageprocessing completion status signal, it sends a delete processingcompletion status signal to the client PC (C2).

[0212] When the client PC receives the delete processing completionstatus signal from the document management server, it outputs aprocessing completion message to the user (displays it on the screen)(A3). Since the output of this delete processing completion message isnot always necessary, the delete processing completion status signal mayalso be ignored.

[0213] Next, a flow of the processing in which the document data storedin the document management server is retrieved from the client PC isdescribed. FIG. 23 is a flowchart showing a flow of the retrievalprocessing of this embodiment.

[0214] When document data is retrieved from the client PC, first aretrieval condition needs to be determined. For example, there are thefollowing specification methods regarding the retrieval condition of thedocument data.

[0215] Retrieval from the character string contained in a title

[0216] Retrieval from the author (creator)

[0217] Retrieval from the creation date

[0218] Retrieval from the character string contained in the text

[0219] This retrieval condition is specified on the client PC and sentto the document management server. Subsequently, a retrieval processingexecution instruction is sent (A0).

[0220] When the document management server receives the retrievalcondition and the retrieval processing execution instruction from theclient PC, it retrieves the document data stored in the documentmanagement server based on the retrieval condition. When the documentmanagement server completes retrieval processing, it transfers aretrieval result to the client PC (C0).

[0221] When the client PC receives the retrieval result from thedocument management server, it outputs the retrieval result (displays iton the screen). The user obtains desired document data from the outputretrieval result (A1).

[0222] Next, a flow of the processing in which the document data storedin the storage server is recovered is described. FIG. 24 is a flowchartshowing a flow of the recovery processing of this embodiment. Similarlyto the retrieval processing described previously, a retrieval conditionis specified by the client PC and the retrieval condition and aretrieval processing execution instruction are sent to the documentmanagement server.

[0223] When the document management server receives the retrievalcondition and the retrieval processing execution instruction, itretrieves the document data stored in the document management serverbased on the retrieval condition. As a result of this retrieval, ifthere is no document data that matches the condition, the documentmanagement server transfers the retrieval condition to the temporarystorage server (C0).

[0224] When the temporary storage server receives the retrievalcondition from the document management server, it retrieves the documentdata stored in the storage server based on the condition. When retrievalprocessing is completed, it transfers the retrieval result to thedocument management server (D0).

[0225] The document management server sends a document data transferinstruction to the temporary storage server based on the retrievalresult received from the temporary storage server so that necessarydocument data can be transferred from the temporary storage server tothe document management server (C1).

[0226] When the temporary server receives the document data transferinstruction from the document management server, it transfers thedocument data that matches instructed contents to the document controlserver (D1).

[0227] When the document management server receives document data fromthe temporary storage server, it transfers the retrieval result to theclient PC (C2).

[0228] When the client PC receives the retrieval result from thedocument management, it outputs the retrieval result (plays it on thescreen). The user obtains desired document data from the outputretrieval result (A1).

[0229] In this embodiment, basically, a contract that uses the temporarystorage server needs previously to be concluded so that the temporarystorage server can be used. This contract may also be concluded for eachuser and for each document management server. The contract may also beconcluded for each user's network environment.

[0230] In the contract for each user, even for the user who is using thesame document management server, only the document data containing adeletion instruction from a contracted user is stored by the temporarystorage server.

[0231] Further, in the contract for each document management server,when there are multiple document management servers in the userenvironment, only the document data of the document management serverthat is entering into a contract with the temporary storage server istransferred to the temporary storage server when the deletioninstruction is given.

[0232] In this embodiment, fees are charged when the user uses thetemporary storage server. The contents of accounting depend on thefollowing items.

[0233] Shelf life (Storage for a certain period is free of charge.)

[0234] Number of stored document data items (Capacity)

[0235] Number of storage times (Document data for a specific number ofitems is free of charge.) Further, when a recovery instruction is givenfrom the document management server within a fixed period of a shelflife, a service free of charge is also acceptable.

[0236] Fees may also be charged to the user every time a fee occurs.Further, it is also possible to pay a fixed amount of money previouslyas a prepaid system and subtract the amount from the prepaid amountevery time a fee occurs.

[0237] In addition, although the system of this embodiment is describedin the configuration in which there are a single document server and asingle temporary storage server, the present invention is not limited tothis configuration, and functions even in the configuration in whichthere are multiple document servers and multiple temporary storageservers.

[0238] Further, in this embodiment, document data is handled as deletionand recovery objects. This embodiment is not limited to the documentdata and can also apply to another data and information. For example,image data photographed by a digital camera, voice data, and numericaldata is also acceptable.

[0239] Next, a fifth embodiment of the present invention is described.In the fifth embodiment, the deletion data storage service of a networkpersonal digital terminal is used as an example.

[0240] That is, this embodiment relates to a data management servicethat uses a personal digital assistant connected to a network (theInternet). The personal digital assistant here indicates a cellularphone having the Internet connection function, an electronic note havingthe network connection function, and a mini-notebook PC.

[0241] The personal digital assistant connected to the network can readand write e-mails and browse home pages, and image data and documentdata are retained and can be browsed as the case may be. The personaldigital assistant of today has the function of handling various data inthis manner.

[0242] Most of personal digital assistants are reduced in their sizessince importance is attached to their portability. The reduction oftheir sizes is affected and the capacity of the storing unit inside apersonal digital assistant is very small. Accordingly, since thecapacity of the data that can be held by the personal digital assistantis small, the user uses the personal digital assistant to create data onit each time and as the case may be, transfer the data to it, and browsethe data.

[0243] Data transfer sources are a personal computer the user possessesand a server on a network (the Internet).

[0244] Since the storage capacity of a personal digital terminal issmall, the storage capacity is filled immediately when the userfrequently uses the personal digital assistant and transfers multimediadata such as music and images to the personal digital assistant.

[0245] Under the circumstances, the user has had to transfer anotherdata to the personal digital assistant after the user deletes the dataalready provided in the personal digital assistant and secures thecapacity. However, when the data deleted on the personal digitalassistant is required again, the data has been unable to be reused. Inthis embodiment, such a shortcoming is solved.

[0246] In this embodiment, when the user issues a deletion instructionto specific data, the data of which the deletion instruction is receivedon the user's personal digital assistant is transferred to the temporarystorage server installed on the network via a network, and then the dataprovided in the personal digital assistant is deleted. Accordingly, whenthe data is required again, the deleted data can be recovered by makingan inquiry from the personal digital assistant to the temporary storageserver.

[0247]FIG. 25 is the system block diagram of this embodiment. A user'spersonal digital assistant K is connected to a network by radio. Forradio connection, the personal digital assistant is connected to thenetwork N via a radio tower or the like.

[0248] The personal digital assistant may also pass through acommunication satellite or the like as a connecting path to the radiotower. The temporary storage server HS is connected onto the network N.The temporary storage server has a mass storage unit and can store datatransferred from the personal digital assistant K. For data storage, thedata is stored after an identifier that can uniquely identify the datais attached.

[0249]FIG. 26 is a flowchart showing a flow of the delete processing inthe system of this embodiment. First, the user specifies data to bedeleted on the personal digital terminal and specifies delete processingexecution (A0).

[0250] When the personal digital assistant receives a delete processingexecution instruction, it transfers deletion object data to thetemporary storage server (A1).

[0251] When the temporary server receives the data sent from thepersonal digital assistant, it stores the data into the storing unit ofthe temporary storage server (C0). This storing unit may be a magneticmedium such as an HDD a magneto-optical medium such as a DVD-RAM or asemiconductor medium such as a memory. Further, the storing unit doesnot have to be provided inside the temporary storage server.

[0252] When there is no storing unit inside the temporary storageserver, a server that has the storing unit is installed where data caneasily be accessed from the temporary storage server via the network.For data storage, the data is stored after an identifier that canuniquely identify the data is attached.

[0253] Identification data contains information identifies whichpersonal digital assistant the data is sent from and information such asstorage date and data sizes.

[0254] When the temporary storage server completes storage processing,it sends a delete processing completion status signal to the personaldigital assistant.

[0255] When the personal digital assistant receives the deleteprocessing completion status signal from the temporary storage server,it outputs a processing completion message to the user (displays it onthe screen) (A2). Since the output of this delete processing completionmessage is not always necessary, the delete processing completion statussignal may also be ignored.

[0256] The deletion object data from the personal digital assistant tothe temporary storage server does not necessarily have to be transferredimmediately after the delete processing execution is received from theuser. The data may also be transferred at the time (for example, atnight) when the user's personal digital assistant is not used. In thatcase, a delete processing completion status signal does not necessarilyhave to be received by the personal digital assistant at the end.

[0257]FIG. 27 is a flowchart showing a flow of the recovery processingin the system of this embodiment. When the user must recover the datathat is not provided on the personal digital assistant and has beendeleted before, first, conditions of the data to be recovered arespecified. The conditions to be specified are the deletion date of data,title of data, creator of data, and data sender.

[0258] When the conditions of the data to be recovered are decided, theuser instructs the personal digital assistant to retrieve the data thatmatches the condition. When the personal digital assistant receives aretrieval instruction from the user, it transfers a retrieval conditionto the temporary storage server.

[0259] When the temporary storage server receives the retrievalcondition from the personal digital assistant, it retrieves the datathat matches this condition from the storing unit. When the retrievalprocessing is completed, the retrieval result is sent to the personaldigital assistant (C0).

[0260] When the personal digital assistant receives the retrieval resultfrom the temporary storage server, it outputs the retrieval result(displays it on the screen). The user selects the desired data to berecovered from the output retrieval result. When the selection of thedata to be recovered is completed, the personal digital assistanttransfers a recovery object data list to the temporary storage server(A1).

[0261] When the temporary storage server receives the recovery objectdata list, it transfers the data described in the list to the personaldigital assistant (C1).

[0262] The personal digital assistant receives data from the temporarystorage server (A2).

[0263] Data can be recovered according to the flow of the aboveprocessing. Further, in this example, a condition of the data to berecovered is specified and retrieved, and the data to be recovered isselected from a retrieval result. However, it is possible to browse alist of all data stored in the temporary storage server with thepersonal digital assistant and select from it the data to be recovered.At that time, a list of data is deleted by the personal digitalassistant and the transferred data is displayed.

[0264] Further, in this embodiment, in the same manner as the fourthembodiment, a contract in which the temporary storage server ispreviously used and fees may also be charged in accordance with the useof the temporary storage server.

[0265] As described above, according to the present invention, thefollowing effect is obtained. That is, unnecessary information isdetected from electronic information stored in a storing unit and canquickly be deleted. As a result, only information necessary for thestoring unit can be stored. Only the information useful for informationretrieval is retrieved and the quality of a retrieval result can beimproved.

[0266] The entire disclosure of Japanese Patent Application No.2000-327970 filed on Oct. 27, 2000 including specification, claims,drawings and abstract is incorporated herein by reference in itsentirety.

What is claimed is:
 1. An electronic information management server,comprising: feature extracting means for extracting a feature ofelectronic information stored in storing means connected to a network;deciding means for deciding whether the electronic information is to bedeleted from the feature extracted by the feature extracting means basedon an instruction from a client; and deleting means for deleting fromthe storing means via the network the electronic information decided tobe deleted by the deciding means.
 2. An electronic informationmanagement server, comprising: storing means connected to a network forstoring electronic information; feature extracting means for extractinga feature of the electronic information stored in the storing means;deciding means for deciding whether the electronic information is to bedeleted from the feature extracted by the feature extracting means basedon an instruction of a client; and deleting means for deleting from thestoring means the electronic information decided to be deleted by thedeciding means.
 3. An electronic information management server,comprising: storing means connected to a network for storing electronicinformation; feature extracting means for extracting a feature of theelectronic information stored in the storing means; instructing andoperating means for instructing the feature of the electronicinformation; deciding means for deciding whether the electronicinformation is to be deleted from the feature extracted by the featureextracting means based on an instruction from the instructing andoperating means; and deleting means for deleting from the storing meansthe electronic information decided to be deleted by the deciding means.4. The electronic information management server according to claim 1,wherein the deciding means decides whether the electronic information isto be deleted based on a feature comprising a character string.
 5. Theelectronic information management according to claim 1, wherein thedeciding means decides whether the electronic information is to bedeleted based on a feature comprising an image.
 6. The electronicinformation management server according to claim 1, wherein the decidingmeans decides whether the electronic information is to be deleted basedon a feature comprising a similar image.
 7. The electronic informationmanagement server according to claim 1, wherein the deciding meansdecides that other electronic information related to specific electronicinformation is also deleted together with the specific electronicinformation decided to be deleted based on the feature.
 8. An electronicinformation management server, comprising: temporarily storing means fortemporarily storing electronic information sent via a network; anddeleting means for deleting the electronic information stored in thetemporarily storing means at a predetermined timing.
 9. The electronicinformation management server according to claim 8, wherein the deletingmeans deletes the electronic information from the temporarily storingmeans after a predetermined period of time has elapsed.
 10. Anelectronic information management client that instructs deletion ofelectronic information stored in storing means connected to a network,comprising: instructing and operating means for instructing a feature ofthe electronic information to be deleted.
 11. The electronic informationmanagement client according to claim 10, further comprising inputtingmeans for inputting the feature and transferring it to the instructingand operating means.
 12. An electronic information management method,comprising the steps of: extracting a feature of electronic informationstored in storing means connected to a network; deciding whether theelectronic information is to be deleted from a previously extractedfeature based on an instruction from a client; and deleting from thestoring means via the network the electronic information decided to bedeleted.
 13. An electronic information management method, comprising thesteps of: storing predetermined electronic information; extracting afeature of the stored electronic information; deciding whether theelectronic information is to be deleted from a previously extractedfeature based on an instruction from a client; and deleting theelectronic information decided to be deleted.
 14. The electronicinformation management method according to claim 12, wherein whether theelectronic information is to be deleted is decided based on a featurecomprising a character string instructed by the client.
 15. Theelectronic information management method according to claim 12, whereinwhether the electronic information is to be deleted is decided based ona feature comprising an image instructed by the client.
 16. Theelectronic information management method according to claim 12, whereinwhether the electronic information is to be deleted is decided byobtaining a feature comprising an image instructed by the client basedon image features having a similar image of the image.
 17. Theelectronic information management method according to claim 12, whereinother electronic information related to specific electronic informationis also decided as a deletion object together with the specificelectronic information decided to be deleted based on the feature. 18.An electronic information management method, comprising the steps of:temporarily storing electronic information sent from a network; anddeleting the temporarily stored electronic information at apredetermined timing.
 19. The electronic information management methodaccording to claim 18, wherein the temporarily stored electronicinformation is deleted after a predetermined period of time has elapsed.20. The electronic information management method according to claim 18,wherein the temporarily stored electronic information is deleted basedon an instruction from a sender of the electronic information.
 21. Theelectronic information management method according to claim 18, whereinthe temporarily stored electronic information is transferred based on aninstruction from a sender of the electronic information.
 22. Anelectronic information management method, when electronic informationstored in storing means connected to a network is deleted, comprisingthe steps of: inputting a feature of the electronic information to bedeleted; and giving a deletion execution instruction to the electronicinformation to be deleted extracted from the storing means according tothe input feature.
 23. An electronic information management method,comprising the steps of: inputting a feature of electronic informationfrom terminal equipment and extracting information to be deleted fromthe electronic information stored in storing means of the terminalequipment; and deleting the electronic information extracted as thedeletion object from the storing means according to an instruction fromthe terminal equipment.
 24. An electronic information management method,comprising the steps of: inputting a feature of electronic informationfrom terminal equipment and extracting information to be deleted fromthe electronic information stored in storing means of the terminalequipment; transferring the electronic information extracted as thedeletion object from the storing means to a temporary storage server viaa network according to an instruction from the terminal equipment; anddeleting the transferred electronic information from the storing means.25. The electronic information management method according to claim 24,wherein a deletion timing of the electronic information stored in thetemporary storage server is instructed by the terminal equipment. 26.The electronic information management method according to claim 24,wherein a transfer of electronic information stored in the temporarystorage server to the terminal equipment is instructed by the terminalequipment.
 27. An electronic information management method, comprisingthe steps of: accepting an input of a feature of electronic informationfrom terminal equipment and extracting information to be deleted fromthe electronic information stored in storing means of the terminalequipment; and deleting electronic information extracted as the deletionobject from the storing means according to an instruction from theterminal equipment.
 28. A recording medium readable by a computer,recording a program of instructions executable by the computer toperform an electronic information management method, the methodcomprising the steps of: extracting a feature of electronic informationstored in storing means connected to a network; deciding whether theelectronic information is to be deleted from a previously extractedfeature based on an instruction from a client; and deleting from thestoring means via a network the electronic information decided to bedeleted.
 29. A recording medium readable by a computer, recording aprogram of instructions executable by the computer to perform anelectronic information management method, the method comprising thesteps of: storing electronic information sent via a network in temporarystoring means; and deleting the electronic information stored in thetemporary storing means at a predetermined timing.
 30. A recordingmedium readable by a computer, recording a program of instructionsexecutable by the computer to perform an electronic informationmanagement method, when electronic information stored in storing meansconnected to a network is deleted, the method comprising the steps of:accepting a feature of the electronic information to be deleted; andaccepting a deletion execution instruction for the electronicinformation to be deleted extracted from the storing means according tothe accepted feature.
 31. A recording medium readable by a computer,recording a program of instructions executable by the computer toperform an electronic information management method, the methodcomprising the steps of: accepting an input of a feature of electronicinformation from terminal equipment and extracting information to bedeleted from the electronic information stored in storing means of theterminal equipment; and transferring the electronic informationextracted as the deletion object from the storing means to a temporarystorage server via a network according to an instruction from theterminal equipment and deleting the transferred electronic informationfrom the storing means.